Automotive fuel storage system with in-tank fuel encapsulation system

1. Field of the Invention

The present invention relates to a system for coating the interior walls of a fuel tank with a barrier fluid in the event of a potential fuel-spill emergency, so as to encapsulate fuel within the tank and inhibit the flow of fuel from the tank.

2. Disclosure Information

Police vehicles are subject to increased exposure to collisions, particularly high-speed rear-end collisions, arising from the need for police officers to stop on the shoulders, or even in the traffic lanes, of busy highways. Unfortunately, other motorists are known to collide with police vehicles employed in this manner. These accidents can compromise the fuel system on any vehicle and may cause fires. The present system is intended to suppress the spread of fuel which could feed such a fire.

According to an aspect of the present invention, an automotive fuel storage system includes a fuel storage tank installed in a vehicle, and a barrier fluid tank containing a supply of barrier fluid. A distribution system, connected with the barrier fluid tank and with the fuel storage tank, distributes barrier fluid in a laminar flow about the outer periphery of fuel contained within the storage tank, creating a boundary layer of more viscous fluid, such that exfiltration of fuel from the fuel storage tank will be inhibited. The barrier fluid tank may be located externally to the fuel storage tank or internally within the fuel storage tank.

According to another aspect of the present invention, barrier fluid is constituted as a viscous, flowable fluid having a vapor pressure less than that of motor gasoline. Barrier fluid may include a viscosity modifier such as ethylene-propylene copolymers or styrene-butadiene copolymers. Further, the barrier fluid preferably has a flammability less than the flammability of gasoline.

As used herein, the term “barrier fluid” means a flowable fluid, which, upon being introduced between the inner surfaces of a fuel tank and liquid fuel within the tank, creates a boundary layer of more viscous fluid which inhibits free flow of the fuel, such as gasoline, through a breach in a damaged tank wall.

According to another aspect of the present invention, the barrier fluid may include a hydrocarbon liquid thickened with a metallic soap. Barrier fluid may also include polymethacrylate.

According to another aspect of the present invention, a fuel storage system includes a pressure relief valve mounted in a wall of the fuel storage tank.

According to another aspect of the present invention, a controller for triggering the discharge of a propellant within the barrier fluid tank preferably employs pre-crash sensing such as radar or ultrasonic detection, so as to deploy the fuel encapsulation system early during a collision sequence.

It is an advantage of the present automotive fuel storage system that encapsulation of the fuel will inhibit exfiltration of fuel through a damaged tank such as that occurring during a collision, so as to lessen the fire risk from the fuel contained within the tank.

Other advantages, as well as features of the present invention will become apparent to the reader of this specification.

FIG. 1 is a perspective view of a vehicle having an automotive fuel storage system with an encapsulation system according to the present invention.

FIG. 2 is a sectional view, partially in elevation, of the fuel tank shown in FIG. 1 , taken along the line 2 - 2 of FIG. 1 .

FIG. 3 illustrates the fuel tank of FIG. 1 , taken along the line 3 - 3 of FIG. 1 .

FIG. 4 is similar to FIG. 3 but shows a system in which a barrier fluid tank is contained within the fuel storage tank itself.

As shown in FIG. 1 , vehicle 100 has a fuel storage tank, 104 , containing a quantity of fuel 106 therein ( FIGS. 2 , 3 , 4 ). Barrier fluid tank 108 is situated externally of fuel tank 104 in FIG. 1 and upon command from controller 112 , barrier fluid 110 will be flowed into fuel tank 104 by means of a distribution system including manifold 116 and a number of flow nozzles 120 , which are shown in FIGS. 2-4 . Flow nozzles 120 include not only wide angle fan nozzles 120 , but also, wall nozzles 122 , which cause barrier fluid to flow tangentially along the walls of fuel tank 104 . The action of wall nozzles 122 , when combined with wide angle spray nozzles 120 effectively coat the outer surface of the fuel with barrier fluid 110 , encapsulating the fuel within the tank. In essence, flow nozzles 120 and 122 are located and configured so as to distribute barrier fluid in a tangential flow along at least some of the interior surfaces of said fuel storage tank. Flow nozzles 120 and 122 do not function like injector nozzles because the pressure, nozzle flow pattern, and viscosity of the barrier fluid cause do not cause barrier fluid 110 to bore into the fuel; rather, barrier fluid 110 coats all of the outer surfaces of the fuel volume with a boundary layer which is more viscous than the fuel.

By increasing the localized viscosity of the fluid within a boundary layer at the tank walls, barrier fluid 110 inhibits the exfiltration, or flow, of fuel through a breach which might erupt through a fuel tank wall due to a collision. Barrier fluid 110 may comprise any of a number of viscosity increasing fluids known to those skilled in the art such as greases or other hydrocarbon liquids thickened with either metallic soap, or viscosity modifiers such as polymethacrylate, styrene-butadiene, or ethylene-propylene copolymers. What is important is that the barrier fluid be introduced quickly into the fuel tank so as to coat the surface of the fuel during a collision event. If the fuel is prevented from leaving the tank for only a few seconds at the beginning of a collision event, the chances of avoiding a fire are greatly improved.

If desired, barrier fluid tank 108 , including propellant 124 , may be mounted within fuel tank 104 , as shown in FIG. 4 . If internal mounting is chosen, manifolding 116 may also be placed internally within fuel tank 104 as well. Regardless of the location of propellant 124 , burst disc 114 ( FIG. 2 ) limits over pressurization of tank 104 when barrier fluid 110 is introduced.

Although the present invention has been described in connection with particular embodiments thereof, it is to be understood that various modifications, alterations, and adaptations may be made by those skilled in the art without departing from the spirit and scope of the invention set forth in the following claims.